Limp Mode , Reduced Engine Performance mystery

[Beneb]

Hey, I've searched this forum and all of them out there. Still looking for an answer and any help would be appreciated.

I'll be driving and all the sudden the car will go into different modes. I'll get a 'reduced engine performance' message and the car will do one of three things: be very slow and hesitant, the RPM's will barely rev and it seems like the turbo isn't working; have a higher idle and surge when the gas pedal is pressed and will climb in RPM's when in park or nuetral ; or go into full on 'Limp' Mode.

It has been doing this off and on for a while and seems to happen when I hit a hard bump, or sometimes for no reason at all. The problem will go away for a few months, but always seems to come back.

I have already replaced a throttle body , still have the original, and cleaned and checked out most connections relating to the throttle body. I don't think it is a problem with the throttle body itself, as it is a 2006 and volvo had fixed the failing etm issue by then.

The following codes have been stored.

p2111
p2135
p0638
p0507
p1167.

At this point i'm basically stumped. Any help would be appreciated.

 

[Kevin James]

Hi, Did you ever get the Reduced Engine Performance" issue figured out? We have a 2005 s40 T5 with the same issue for the last year and a half. Getting expensive trying to keep this car on the road.

 

[Bob Fincham]

Try removing the multi-plug connectors from the CEM unit and then push them back in hard as you can. I've had a similar problem with my S40 2.0D. The main dealer tried telling me the CEM unit needed replacing which is quite expensive. I did the above and it seems to have worked. It's lasted 2-3 years so worth a try.